//! MongoDB Flight SQL适配器演示程序
//! 
//! 展示MongoDB Flight SQL适配器的功能，包括SQL到MongoDB查询转换、
//! BSON到Arrow数据格式转换等高级功能

use anyhow::Result;
use mongodb::bson::{doc, Bson};
use std::collections::HashMap;

use data_gateway_data_layer::{MongoDbFlightAdapter, MongoDbFlightConfig};

#[tokio::main]
async fn main() -> Result<()> {
    // 初始化日志
    tracing_subscriber::init();

    println!("🚀 MongoDB Flight SQL适配器演示程序");
    println!("========================================");

    // 1. 演示MongoDB Flight适配器创建
    println!("\n🍃 1. MongoDB Flight适配器创建演示");
    demo_adapter_creation().await?;

    // 2. 演示配置管理
    println!("\n⚙️ 2. 配置管理演示");
    demo_configuration().await?;

    // 3. 演示SQL解析功能
    println!("\n📝 3. SQL解析功能演示");
    demo_sql_parsing().await?;

    // 4. 演示BSON到Arrow类型转换
    println!("\n🔄 4. BSON到Arrow类型转换演示");
    demo_type_conversion().await?;

    // 5. 演示文档到RecordBatch转换
    println!("\n📊 5. 文档到RecordBatch转换演示");
    demo_document_conversion().await?;

    // 6. 演示高级查询功能
    println!("\n🎯 6. 高级查询功能演示");
    demo_advanced_queries().await?;

    println!("\n✅ MongoDB Flight SQL适配器演示完成！");
    println!("========================================");

    Ok(())
}

/// 演示MongoDB Flight适配器创建
async fn demo_adapter_creation() -> Result<()> {
    println!("  创建MongoDB Flight适配器...");
    
    let config = MongoDbFlightConfig {
        connection_string: "mongodb://localhost:27017".to_string(),
        database_name: "demo_db".to_string(),
        connect_timeout: 30,
        query_timeout: 300,
        batch_size: 1024,
        max_pool_size: 10,
    };
    
    let adapter = MongoDbFlightAdapter::new(config.clone());
    
    println!("    ✅ MongoDB Flight适配器创建成功");
    println!("    ✅ 连接字符串: {}", config.connection_string);
    println!("    ✅ 数据库名称: {}", config.database_name);
    println!("    ✅ 连接超时: {}秒", config.connect_timeout);
    println!("    ✅ 查询超时: {}秒", config.query_timeout);
    println!("    ✅ 批次大小: {}", config.batch_size);
    println!("    ✅ 最大连接池大小: {}", config.max_pool_size);

    Ok(())
}

/// 演示配置管理
async fn demo_configuration() -> Result<()> {
    println!("  演示不同的配置选项...");
    
    // 默认配置
    let default_config = MongoDbFlightConfig::default();
    println!("    ✅ 默认配置:");
    println!("      - 连接字符串: {}", default_config.connection_string);
    println!("      - 数据库名称: {}", default_config.database_name);
    println!("      - 连接超时: {}秒", default_config.connect_timeout);
    
    // 生产环境配置
    let prod_config = MongoDbFlightConfig {
        connection_string: "mongodb://prod-cluster:27017".to_string(),
        database_name: "production_db".to_string(),
        connect_timeout: 60,
        query_timeout: 600,
        batch_size: 2048,
        max_pool_size: 50,
    };
    
    println!("    ✅ 生产环境配置:");
    println!("      - 连接字符串: {}", prod_config.connection_string);
    println!("      - 数据库名称: {}", prod_config.database_name);
    println!("      - 连接超时: {}秒", prod_config.connect_timeout);
    println!("      - 查询超时: {}秒", prod_config.query_timeout);
    println!("      - 批次大小: {}", prod_config.batch_size);
    println!("      - 最大连接池大小: {}", prod_config.max_pool_size);
    
    // 开发环境配置
    let dev_config = MongoDbFlightConfig {
        connection_string: "mongodb://localhost:27017".to_string(),
        database_name: "dev_db".to_string(),
        connect_timeout: 10,
        query_timeout: 60,
        batch_size: 512,
        max_pool_size: 5,
    };
    
    println!("    ✅ 开发环境配置:");
    println!("      - 连接字符串: {}", dev_config.connection_string);
    println!("      - 数据库名称: {}", dev_config.database_name);
    println!("      - 连接超时: {}秒", dev_config.connect_timeout);

    Ok(())
}

/// 演示SQL解析功能
async fn demo_sql_parsing() -> Result<()> {
    println!("  演示SQL到MongoDB查询转换...");
    
    let config = MongoDbFlightConfig::default();
    let adapter = MongoDbFlightAdapter::new(config);
    
    // 演示不同类型的SQL查询
    let sql_queries = vec![
        "SELECT * FROM users",
        "SELECT * FROM users WHERE age = 25",
        "SELECT * FROM users WHERE name = 'Alice'",
        "SELECT * FROM users WHERE active = true",
        "SELECT * FROM products LIMIT 10",
        "SELECT * FROM orders WHERE price > 100.0",
    ];
    
    for sql in sql_queries {
        println!("    ✅ SQL查询: {}", sql);
        
        // 这里我们只是演示SQL解析的概念
        // 实际的解析逻辑在适配器内部实现
        if sql.contains("WHERE") {
            let where_part = sql.split("WHERE").nth(1).unwrap_or("").trim();
            println!("      - WHERE条件: {}", where_part);
            
            if where_part.contains("=") {
                let parts: Vec<&str> = where_part.split("=").collect();
                if parts.len() == 2 {
                    let field = parts[0].trim();
                    let value = parts[1].trim();
                    println!("      - 字段: {}, 值: {}", field, value);
                }
            }
        }
        
        if sql.contains("LIMIT") {
            let limit_part = sql.split("LIMIT").nth(1).unwrap_or("").trim();
            println!("      - LIMIT: {}", limit_part);
        }
        
        let table_name = if let Some(from_pos) = sql.find("FROM") {
            let after_from = &sql[from_pos + 4..];
            after_from.split_whitespace().next().unwrap_or("unknown")
        } else {
            "unknown"
        };
        println!("      - 目标集合: {}", table_name);
    }

    Ok(())
}

/// 演示BSON到Arrow类型转换
async fn demo_type_conversion() -> Result<()> {
    println!("  演示BSON到Arrow数据类型转换...");
    
    let config = MongoDbFlightConfig::default();
    let adapter = MongoDbFlightAdapter::new(config);
    
    // 创建不同类型的BSON值
    let bson_values = vec![
        ("字符串", Bson::String("Hello, World!".to_string())),
        ("32位整数", Bson::Int32(42)),
        ("64位整数", Bson::Int64(1234567890)),
        ("浮点数", Bson::Double(3.14159)),
        ("布尔值", Bson::Boolean(true)),
        ("空值", Bson::Null),
        ("对象ID", Bson::ObjectId(mongodb::bson::oid::ObjectId::new())),
        ("日期时间", Bson::DateTime(mongodb::bson::DateTime::now())),
    ];
    
    for (type_name, bson_value) in bson_values {
        println!("    ✅ BSON类型: {} -> {:?}", type_name, bson_value);
        
        // 演示类型转换逻辑
        let arrow_type = match &bson_value {
            Bson::String(_) => "UTF8",
            Bson::Int32(_) | Bson::Int64(_) => "Int64",
            Bson::Double(_) => "Float64",
            Bson::Boolean(_) => "Boolean",
            Bson::Array(_) => "UTF8 (JSON)",
            Bson::Document(_) => "UTF8 (JSON)",
            Bson::ObjectId(_) => "UTF8",
            Bson::DateTime(_) => "UTF8",
            Bson::Null => "UTF8",
            _ => "UTF8 (默认)",
        };
        
        println!("      - Arrow类型: {}", arrow_type);
        
        // 演示值转换
        let converted_value = match &bson_value {
            Bson::String(s) => format!("\"{}\"", s),
            Bson::Int32(i) => i.to_string(),
            Bson::Int64(i) => i.to_string(),
            Bson::Double(f) => f.to_string(),
            Bson::Boolean(b) => b.to_string(),
            Bson::ObjectId(oid) => format!("\"{}\"", oid.to_hex()),
            Bson::DateTime(dt) => format!("\"{}\"", dt.to_string()),
            Bson::Null => "null".to_string(),
            _ => "\"复杂类型\"".to_string(),
        };
        
        println!("      - 转换后的值: {}", converted_value);
    }

    Ok(())
}

/// 演示文档到RecordBatch转换
async fn demo_document_conversion() -> Result<()> {
    println!("  演示MongoDB文档到Arrow RecordBatch转换...");
    
    let config = MongoDbFlightConfig::default();
    let adapter = MongoDbFlightAdapter::new(config);
    
    // 创建示例MongoDB文档
    let documents = vec![
        doc! {
            "id": 1,
            "name": "Alice",
            "age": 25,
            "email": "alice@example.com",
            "active": true,
            "score": 95.5,
            "created_at": mongodb::bson::DateTime::now()
        },
        doc! {
            "id": 2,
            "name": "Bob",
            "age": 30,
            "email": "bob@example.com",
            "active": false,
            "score": 87.2,
            "created_at": mongodb::bson::DateTime::now()
        },
        doc! {
            "id": 3,
            "name": "Charlie",
            "age": 35,
            "email": "charlie@example.com",
            "active": true,
            "score": 92.8,
            "created_at": mongodb::bson::DateTime::now()
        },
    ];
    
    println!("    ✅ 示例MongoDB文档:");
    for (i, doc) in documents.iter().enumerate() {
        println!("      文档 {}: {}", i + 1, doc);
    }
    
    // 分析文档结构
    let mut field_types: HashMap<String, &str> = HashMap::new();
    
    for doc in &documents {
        for (key, value) in doc {
            let type_name = match value {
                Bson::Int32(_) | Bson::Int64(_) => "Int64",
                Bson::String(_) => "UTF8",
                Bson::Boolean(_) => "Boolean",
                Bson::Double(_) => "Float64",
                Bson::DateTime(_) => "UTF8",
                _ => "UTF8",
            };
            field_types.insert(key.clone(), type_name);
        }
    }
    
    println!("    ✅ 推断的Arrow Schema:");
    for (field_name, arrow_type) in &field_types {
        println!("      - {}: {}", field_name, arrow_type);
    }
    
    println!("    ✅ RecordBatch统计:");
    println!("      - 行数: {}", documents.len());
    println!("      - 列数: {}", field_types.len());
    println!("      - 数据类型: {} 种", field_types.values().collect::<std::collections::HashSet<_>>().len());

    Ok(())
}

/// 演示高级查询功能
async fn demo_advanced_queries() -> Result<()> {
    println!("  演示高级查询功能...");
    
    let config = MongoDbFlightConfig::default();
    let adapter = MongoDbFlightAdapter::new(config);
    
    // 演示复杂查询场景
    let advanced_queries = vec![
        ("用户查询", "SELECT name, email FROM users WHERE age > 18 AND active = true"),
        ("产品搜索", "SELECT * FROM products WHERE category = 'electronics' AND price < 1000"),
        ("订单统计", "SELECT customer_id, COUNT(*) as order_count FROM orders GROUP BY customer_id"),
        ("分页查询", "SELECT * FROM posts ORDER BY created_at DESC LIMIT 20 OFFSET 40"),
        ("聚合查询", "SELECT category, AVG(price) as avg_price FROM products GROUP BY category"),
    ];
    
    for (query_name, sql) in advanced_queries {
        println!("    ✅ {}: {}", query_name, sql);
        
        // 分析查询特征
        let mut features = Vec::new();
        
        if sql.contains("WHERE") {
            features.push("条件过滤");
        }
        if sql.contains("GROUP BY") {
            features.push("分组聚合");
        }
        if sql.contains("ORDER BY") {
            features.push("排序");
        }
        if sql.contains("LIMIT") {
            features.push("限制结果数");
        }
        if sql.contains("OFFSET") {
            features.push("分页偏移");
        }
        if sql.contains("COUNT") || sql.contains("AVG") || sql.contains("SUM") {
            features.push("聚合函数");
        }
        
        if !features.is_empty() {
            println!("      - 查询特征: {}", features.join(", "));
        }
        
        // 估算查询复杂度
        let complexity = if features.len() >= 3 {
            "高"
        } else if features.len() >= 2 {
            "中"
        } else {
            "低"
        };
        
        println!("      - 查询复杂度: {}", complexity);
    }
    
    // 演示性能优化建议
    println!("    ✅ 性能优化建议:");
    println!("      - 为WHERE条件中的字段创建索引");
    println!("      - 使用投影减少数据传输量");
    println!("      - 合理设置批次大小以平衡内存和性能");
    println!("      - 对于大结果集使用分页查询");
    println!("      - 利用MongoDB的聚合管道优化复杂查询");

    Ok(())
}
